When you run the application, your FireMonkey form is focused on the 3D Rectangle. This is because the Target property of the TCamera is set to Rectangle3D. Moreover, If you click on the 3D rectangle, a OnClick event occurs. The OnClick event enables the TFloatAnimation attached to it. The TFloatAnimation has the PropertyName and Loop properties set to RotationAngle.Y and True, respectively. Therefore, when you click on the 3D rectangle, it begins to rotate until you make another click on it.